Added output of canonical values in identity-constraint error messages.

* xmlschemas.c: Added output of canonical values in
  identity-constraint error messages.
* xmlschemastypes.c include/libxml/xmlschemastypes.h:
  Added xmlSchemaGetCanonValueWhtsp() to the API.
  Further enhancement of the canonical value
  conversion.
* test/schemas/changelog093_0.*: Added test with an XSD
  submitted by Randy J. Ray.
diff --git a/test/schemas/changelog093_0.xml b/test/schemas/changelog093_0.xml
new file mode 100644
index 0000000..4b49612
--- /dev/null
+++ b/test/schemas/changelog093_0.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<changelog
+	xmlns="http://www.blackperl.com/XML/ChangeLog" 
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.blackperl.com/XML/ChangeLog changelog093.xsd">
+	<description lang="PL"/>
+	<description lang="PL"/>
+	<release version="1" date="2005-04-08T21:12:00">
+		<item>
+			<file path="abc"/>
+			<description lang="FR"/>
+		</item>
+	</release>
+</changelog>